Synthesis of Phencyclidine

A phenylmagnesium bromide solution is prepared in a 3-neck reflux apparatus equipped with a calcium chloride drying tube. 30 mL of dry ether, 2.4 g of magnesium turnings and a small crystal of iodine are added to the RBF, then a slow addition of 15.7 g of dry bromobenzene in 15 mL of dry Et2O with stirring. The addition must be carried at a rate where the mixture is continuously at reflux. After which the mixture is refluxed for 3h.

A 1-(1-cyclohexen-1-yl)piperidine salt is prepared in a dry reflux apparatus immersed in an ice bath, equipped with a pressure equalized addition funnel and calcium chloride drying tubes. 16.5 g of 1-(1-cyclohexen-1-yl)piperidine and 50 mL of dry ether is added to the RBF, the funnel is filled with an anhydrous solution prepared from 7.2 of p-TsOH in 40 mL of dry toluene. A slow addition is started with agitation while keeping the temperature below 5°C.

The phenylmagnesium bromide solution, which is cooled down in a freezer, is then poured into a pressure equalized addition funnel equipped with a calcium chloride drying tube, and it is attached to the 1-(1-cyclohexen-1-yl)piperidine salt mixture, immersed in an ice bath. A slow addition is started with agitation while keeping the temperature below 5°C. The mixture is then stirred for 45 minutes at room temperature. The mixture is then poured into a mixture prepared from 200 mL of crushed ice, 20 g of NH4Cl and 20 mL of conc. ammonia solution. The solution is then poured into a separatory funnel and the organic layer is extracted using 2x 50 mL of ether. The organic layer is then washed with 200 mL of water and the layer is dried with a drying agent, filtered and washed with a bit of dry Et2O. The organic layer is then diluted with 150 mL of anhydrous Et2O and a vast stream of dried hydrogen chloride gas is started until no more phencyclidine salt precipitates. The mixture is then filtered and the pure product is dried in a vacuum.

The apparatus

Addition of the solution

Preparation of the enamine salt

Addition of the grignard reactant

The mixture after agitation

Extraction

 

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